1. Field of the Invention
The present invention relates to a transfer apparatus for a substrate such as a semiconductor wafer or the like, and a substrate treatment system having the substrate transfer apparatus.
2. Description of the Related Art
In a photolithography processing in a manufacturing process of a semiconductor device, for example, resist coating treatment of applying a resist solution onto a substrate such as a semiconductor wafer or the like to form a resist film, exposure processing of exposing the resist film to a predetermined pattern, developing treatment of developing the exposed resist film and so on are performed.
A series of the treatments and processing is usually performed using a coating and developing treatment system. The coating and developing treatment system has a cassette station for transferring in/out substrates, for example, in a unit of cassette, a treatment station in which a plurality of treatment apparatuses performing various treatments are arranged, an interface station for delivering the substrate between an adjacent aligner and the treatment station and so on. Further, in the treatment station, a substrate transfer apparatus transferring the substrate to the treatment apparatuses is provided.
For a conventional substrate transfer apparatus, for example, a transfer arm is used which includes a main body portion formed in a substantially circular shape and a holding portion projecting to the inside of the main body portion to hold the lower surface of the substrate. The transfer arm is configured to be movable in the vertical direction and the horizontal direction and rotatable. With this configuration, the substrate transfer apparatus can transfer the substrate to the treatment apparatuses (Japanese Laid-open Patent Publication No. Hei 8-46010).
However, when the transfer arm in the prior art transfers the substrate, a particle adheres to the substrate at a contact surface between the transfer arm and the substrate. The particle is a factor that reduces the yield of products manufactured by the substrate treatment system, bringing about a non-negligible problem with advancement in miniaturization of line width.